Patent Literature 1 discloses a humidity control device including a refrigerant circuit that performs refrigerating cycle operation by circulating a refrigerant. The refrigerant circuit of this humidity control device includes two adsorption heat exchangers each carrying an adsorbent, a compressor, an expansion valve, a four way valve, and refrigerant pipes connecting these. Moreover, in the refrigerant circuit, it is possible to alternately perform refrigerating cycle operation in which high-pressure refrigerant flows in one of the two adsorption heat exchangers and the low-pressure refrigerant flows in the other; and refrigerating cycle operation in which the low-pressure refrigerant flows in the one and the high-pressure refrigerant flows in the other, by switching of a refrigerant circulation direction with the four way valve at a predetermined time interval.
The adsorption heat exchanger in which the low-pressure refrigerant flows serves as an evaporator, and can cause moisture contained in air to be adsorbed (collected) by the adsorbent by heat absorption of the refrigerant. Moreover, the adsorption heat exchanger in which the high-pressure refrigerant flows serves as a condenser, and can cause the moisture adsorbed by the adsorbent to be desorbed by the heat of the refrigerant to give the moisture to air. In this manner, in each of the adsorption heat exchangers, the operation of adsorbing the moisture (collection operation) and the operation of desorbing the moisture (reproduction operation) are alternately performed, with the switching of the four way valve.
Moreover, the humidity control device takes outdoor air and indoor air into a casing containing the refrigerant circuit to cause the same to flow through each of the adsorption heat exchangers, and then generates flows of air such that the air is exhausted to an inside and an outside of a room, respectively. When humidification operation is performed, the outdoor air taken into the casing is caused to flow through the adsorption heat exchanger as the condenser, the air is given the moisture desorbed from the adsorbent, and thereafter, the relevant air is supplied to the inside of the room. Moreover, the indoor air taken into the casing is caused to flow through the adsorption heat exchanger as the evaporator, the moisture in the relevant air is adsorbed by the adsorbent, and then, the relevant air is exhausted to the outside of the room.